Apparatus for flattening sheet glass



sept. 6,-, 1927. 11,641,918

E. J. cAssELMA'N ET AL APPARATUs Fon FLATTENING SHEET GLASS Filed Aug. 16, 1926 2 Sheets-Sheet l INVENTORS um MM N @LAM n JVM Patented Sept. 6, 1927.

lUNITED STATES PATENT OFFICE.,

ELBBIDGE J. CASSELMAN, 0F PITTSBURGH, ANE NICK GRIFFITH AND CHARLES E.

`JOHNSON,I 0F JEANNETTE, PENNSYLVANIA, ASSIGNORS T0 WINDOW G LASS MA- CHINE CMPANY, OF PITTSBURGH, PENNSYLVANIA, A CORPORATION OF NEW JERSEY.

APPARATS ECR FLATTENING SHEET GLASS.

'Application filed August 16., 192.6. Serial No. 129,342.

This invention relates to the flattening of sheet glass, and is applicable not only to the flattening operation )e1-formed on cyl iudcrs or shawls produced vy the cylindenprocess of making Window glass, but also to othei processes such as the well known Colburn process forthe drawing of a flat sheet of glass from a bath.

It has heretofore been common practice in the flattening of glass cylinders or shawls to support 'the cylinder or shawl on the flattening stone and subjectl it to .sufficient heat `to cause it to lay flat thereon. The glass is usually rubbed with a Wooden block to remove any wrinkles therefrom. In'the Colburn process`of making sheet glass the glass is drawn in a continuous sheet and is passed over a bending roll, after which it is supported on a so-called flattening table which is constructed along the same general lines as a chain grate Stoker. The glass is" generally gripped at the edges and stretched while itis thus supported.

If a flattening stone is employed the glass, is sometimes injured by burning. This condition arises when the stone becomes too hot, and as a result small particles on the surface of the stone mark the glass and leave it with the appearance of having been sprinkled with pepper. lVhen glass is supported on the flattening table in the sheet process, it is very frequently marked by such flattening table;

Neither of these defects will appear from a casual glance, but they are very evident to a skilled glass man and they materially reduce the quality of the product.

We provide for flattening4 glass by laying it on the surface of a glass-like body hav- 1ng a higher melting point than the glass itself and subjecting it toa flattening heat.

The glass-like body may consist either of a sheet of glass having a higher melting point than the glass being worked, as, for example, a glass having a higher silica content than the glass being worked. If desired, fused quartz or the like may be used. Fused quartz is a very pure form of silica and is intended to be included when reference is made herein to a material having a high silica content. Y

In the accompanying drawings- Figure 1 is a vertical section through a flattening oven showing our invention as applied to the flattening of glass cylinders or shawls; and i Figure 2 is a longitudinal section through al glass drawing apparatus corresponding generally to the Colburn process. Referring first ,to Figure 1, there is shown a flattening oven indicated generally by the reference character 2. The flattening chaml-er proper is indicated at 3 and a mantle or hanging arch 4 separates it from the socallf-'d dummy oven 5.

AA vflattening wheel 6 is provided in the fiatening oven, a'nd this is connected through suitable gearing T'to a turning device, not shown. The oven is heated by any desired arrangement of burners. These are not shown in the drawing.

Our improved flattening base is mounted on the wheel 6.l In the drawing it is shown as consisting of a flat plate 8 made of a--material having the desired characteristics efnbedded in a. suitable base material 9. The glass, isl ironed through a workin opening' 10 by a wooden block 11 mounted on a rod 12.

Flattening ovens of` this character are generally divided into three parts by hangmg arches such as 4, the several compartmerits being known as the flattenin oven,

lwill reside in the flattening oven proper,

another in the dummy oven, and the remaining two in the cooling and piling oven.

The plates 8 will preferably be made of a fused. high silica substance such as fused quartz or high silica glass.

Figure 2 shows the invention as applied to the Colburn process. The apparatus shown in this drawing corresponds generally to that illustrated and described in the copending application of Henry F. Clark, Serial No 733,746, filed August 23, 1924. In this embodiment of the invention glass in sheet form is drawn from a bath 20 over a bending roll 21 from which it advances to an annealing chamber, indicated generally by the reference character 22. ;In this chamber there is provided aair of sprockets 23 connected by articulate tab'les or beds Q4, each having a glass supporting face made of a glass-like material having; a higher meltinfr point than the sheet of glass being worke on. The upper run of the tables or beds is carried on guides 25, and the edges ofthe glass sheet are held down by presser feet 26 on a chain 27 at either side of the glass sheet.

if desired, the Working surfaces may be ground or they may be left with an original fire polish imparted thereto during the proeess of manufacture.

When glass is flattened aceordin to our invention the objectionable mar ing is eliminated. The flattening base will not soften sutlicieiitly to cause any trouble, if at all, and therefore it will not be scratched by the use of a piling fork or the 'like by which the flattened glass is lifted from the wheel onto the leer rods in the cylinder flattening process.

`We have spoken herein of flattening the glassso as to; produce a plane sheet. lt will be understood, however, that our invention is also applicable to the manufacture of bent .glass and that we use the term flattening as a broad term and intend by it to cover the step of causing the glass sheet to conform to the supporting base regardless of whether said hase is plane or not.

realms We have illustrated and dcribed two preferred forms ofour invention, but it will be understood that the invention is not limited to such forms, as it may be otherwise einbodied and practiced Within the .scope of the following claims. fr W'e claim:

1. Apparatus for flattening glass,- compris# body for the glass to e vflattened, said body being of a glass-like character and having a higher melting point than the glass.

2. Apparatus for flattening glass, coinprising a chamber having therein a supporting body for the glass to be flattened, said body being of a glass-like character and having a higher silica content than the glass being Worked on.

3. Apparatus for flattening glass, comprising a chamber having therein a supporting body for the glass to be attened, said body comprising a fused high silica material having a higher melting point than the glass being worked on.

ln testimony whereof we have hereunto set our hands.

ELBRIDGE J. CASSELMAN. NICK GRIFFITH. CHARLES E. JOHNSON. 

